US 2659497 A
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Nov. 17, 1953 E. A. VERRINDER UNSTACKEIR 7 Sheets-Sheet l Filed July 25. 1949 ATTORNEY NOV 17, 1953 E. A. VERRINDER 2,659,497
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v UNSTACKER Filed July 25, 1949 7 sheets-sheet 7 FIG. J3
Patented Nov. 17, 1953 UNSTACKER Ernest A. Verrinder, Riverside, Calif., assignor to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application July 25, 1949, Serial No. 106,531
This invention relates to devices for breaking down a stack of articles superimposed one upon another in the form of a column by separating the articles from the upper end of said column one at a time.
Devices heretofore provided for this purpose included an elevator for the column of articles and a separating mechanism actuated in timed relation with the elevator. The latter characteristic limited the device, with any given setting of the timed relation between the elevator and separating mechanism, to operation upon stacks of articles in which the latter have a certain xed uniform depth. In order for the device to operate upon articles of a different xed uniform depth, it was necessary to change the timed relation between the functioning of the elevator and of the box separating mechanism. This circumstance constituted a considerable limitation in the utility of these prior devices.
It is an object of the present invention to provide an unstacking device in which the operation of the article separating mechanism is not tied to the elevator in timed relation therewith, but wherein said device is adapted to operate upon articles varying in depth within a substantial range without any adjustment in said device to cause it to function satisfactorily being necessary.
Another object of the invention is to provide such an unstacking device which is suitable for use in handling open boxes loaded with loose material and which separates the individual boxes from the stack without upsetting the same, thereby retaining said material in said boxes.
A further object oi the invention is to providel such an unstacking device which is relatively simple and inexpensive to build and the cost of maintenance of which is low.
The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which:
Fig. l is a side elevational view oi a preferred embodiment of the invention.
Fig. 2 is a front elevational view of Fig. 1 taken in the direction of the arrow 2.
Fig. 3 is a plan view of Fig. 2 with the motor removed to permit the structure therebeneath to be visible.
Fig. 4 is a cross sectional view taken on the line of Fig. l.
Fig. 5 is an enlarged diagrammatic view of a section of one of the stack elevating chains and illustrating a chain lock in an inactive position as when the elevator is lifting a stack.
Fig. 6 is a View similar to Fig. 5 and illustrates the chain lock in operation when the elevator is halted.
Fig. 7 is a diagrammatic sectional view taken on the line 1 7 of Fig. 2 and illustrating the manner in which certain electric switches of the device are actuated.
Fig. 8 is an enlarged detail view of a stack actuated switch of the invention located at the lower end of the elevator.
Fig. 9 is a diagrammatic detail view illustrating the manner in which a stack supporting cradle arm is guided in changing direction at the upper end of the elevator.
Fig. 10 is a diagrammatic View illustrating one position of an uppermost box of a stack just after the action starts by which said box is separated from the rest of the stack.
Fig. 11 is a view similar to Fig. 10 and illustrates a more advanced stage in said box separating action.
Fig. 12 is a wiring diagram showing a preferred electrical wiring system for use in the operation of said invention.
Fig. 13 is a siniplied diagram of the same wiring system shown in Fig. l2.
Referring speciiically to the drawings the nvention is there shown as embodied in an unstacker 25 having a frame 26 the base 2l of which is mounted upon a level floor 2B (Fig. l) there being a suitable pit Z9 formed in said floor to accommodate portions of the structure of the unstacker which extend below the floor line.
The base 2 includes longitudinal members 3! which are connected by a cross member 3i and upon which inclined upright channel members 32 and S3 are mounted. The upper end portions of the channel members 33 are angled relatively to the lower portions thereof so as to lie parallel with the channel members 32 and are connected thereto by spacers 3i and 35 (Fig. l). The channel members 32 are tied together by cross channels 35, Zita and 3l. Mounted on these cross channels are stack guides 38. Mounted on inner faces of channels 32 are inner and outer rising flight chain guides d5 and it (Figs. 2 and 4). Lower` terminal chain guides il (Figs. 1 and 2) are also provided which lie on the same planes as the guides G5 and fit. Chain guides 'i8 and iS (Figs. l, 5 and 5) are mounted on the inner faces of the members 33 near their upper ends. Chain locks 5c are pivotally mounted on the guides 49 for operation as illustrated in Figs. 5 and 6.
Jour-nailed in suitable bearings supported between upper ends of the frame members 32 and 33 is a lifter shaft (Figs. l, 2 and 3) carrying lifter rollers which are preferably provided with rubber treads 5i. Fixed on one end of shaft 55 is a sprocket da (Fig. 2) and on the other end thereof a sprocket 59.
Projecting laterallyv from upper ends of the frame members 32 and 33 are boX structures Sii carrying bearings Gi and 62 (Fig. 2), stub shafts |53 being journalled in said bearings. Secured on the inner ends of these shafts are sprockets Ell having drums G5 formed thereon. Also iixed on shafts 63 just outside the bearings 62 are sprockets 66.
Trained about the sprocket Eid and extending between the chain guides 55, 4.6, its, and 49 and around the reverse turn chain guides :'51 (Fig. l) are endless chains 1t. These chains carry two stack cradles 'ii each of which includes a pair of individual stack supports 's2 mounted on the chains at corresponding points thereon. Each of the supports 12 includes a gib block 13 which is welded to one of the links of one of the chains 19 and has a slot 15. therein which is adapted to receive the adjacent chain guide il@ when that gib is rising with the rising iight of its chain 1d so as to steady the stack support 12 of which it is a part. Said stack support also includes an 1B which is pivotally supported on the gib block 'i3 at 1.53. ri'he outer end of the arm "it is connected by a link chain 'dll with a link in the chain '.5 on which said support 'aE is mounted which is several lings in advance of the link on which the block 13 thereof is mounted.
Supported at its upper end on plates Si ixed on channel members is a take-away box conveyor t2 having a frame 33 on the upper end of which is mounted a shaft 84 carrying a pulley 85 about which is trained a conveyor belt et the latter riding over an arched apron 8i provided on the frame ES as said belt travels downwardly. The frame 53 also has a counter shaft 3B which is connected by a chain 3Q and suitable sprockets to the shaft The shaft 8S has a sprocket 99 on its extending end which is connected by a chain 9| with the sprocket 5S (see Fig. 2).
Extending forwardly from the upper ends of frame member is a rigid frame structure 95 including horizontal channel members diagonal channel members 91, and angle structures S8 and @il which are welded together on the upper edges of the members 91. Fixed on the structures 99 are a pair of bearings its in which a shaft journals, this shaft carrying at its opposite ends a pair of sprockets |62 and, outside one of these sprockets, a sprocket i915. ri'rained about and connecting the sprockets with the sprockets are endless chains ii.
Supported on the structure $8 is a geared electric motor which drives sprockets and H2, the sprocket H5 being connected with a sprocket 53 by a chain ile and the sprocket H2 being connected with the sprocket 33 by a chain lili. Fixed on the frame members to extend downwardly therefrom near their outer ends are housings |28 providing slideways i2| for bearings |22 in which opposite ends of a shaft i223 journal, said housings enclosing coil springs lid which bias said bearings 22 inwardly against the inner ends of runways S2i. The pressure of springs |26.. against bearings |22 is adjustable by screw jacks |25 provided on said housings.
Fixed to inside faces of end portions of the frame members $58 are plates |33 having arms ii 4 and |32 extending downwardly therefrom, the arm |3| being bent outwardly at its lower end. to extend under the shaft |23.
Pivoted at their lower ends to lower ends of arms |232 and |32 are links |33 and |35, the upper ends of which are connected by transverse shafts |35 and ISS. Pivotally mounted on these shafts, with said shafts in spaced relation, are box pusher members |31 each of which has a fork |38 at its inner end in each of which is pivotally mounted a rubber tired roller |353 which is similar to one of the rollers 5S.
Fixed on shaft |23 is a pair of cylindrical metal rollers Iii-, the rollers 55, |36, and E69 on each f side-of the machine lying in the vertical plane of the box guide 38 on that side of the machine (see Figs. 2Y and 3). The unstacker 25 is adapted thandle boxes B the heads of which rest against the beads |50 of the box guides 3S when a stack of these boxes is symmetrically positioned in the machine. Fixed guides |5| are provided near the upper end of the guides 33 to center the boxes of a stack handled in the machine, as this is lifted therein.
Mounted on the oor 28 for feeding stacks S of boxes B into the machine 25 is a floor track |63 comprising a pair of chains |t|, the upper flights or which travel in metal channels |62, and which are driven by sprockets |63 on a shaft |66 rlhe latter shaft is driven by an electric motor (not shown) which is connected thereto by a sprocket IE5 and a chain |66. The shaft |652 also has a sprocket |61 which rotates a drive shaft |68 of an auxiliary iioor track It@ through a chain |15 which connects sprocket |61 with a sprocket |1| which is xed on the shaft Nid.
Electric controls for the unstacker 25 include a switch s-l which is mounted on the floor track |60 so as to be opened by a stack S p ssing thereover; switch s-2 which is positioned to be engaged by the lower end of a stack the latter is delivered into the unstacker switch s-' which located just below one oi' the frame members andv is actuated by a gib each time a cradle 1i rises past said switch; and switch s-4 which is mounted at the upper: end of the machine (Figs. 1 and 2) to be engaged by one of the gibs 13 of each cradle 1| as the latter passes over the zenith of its path of travel, It might be noted here that each of the arms 18 has provided thereon a boss I1?. which engages the drum 55 of the adjacent sprocket 6ft as the gib 13 on which said arm is mounted changes direction at the upper end of the unstacker elevator (Figs. 2 and 9) thereby smoothly reversing the movement of supports 12 about shaft 63.
Mounted on structure 98 is a switch s|1 which is opened whenever a box gets caught on the box therebeneath and thus, failing to be discharged over the rollers 55, rises into contact with a plate |15 supported on a lever |16 which overlies switch s-I'I and is pivotally mounted on structure 98. The opening of switch s|1 stops motor Il until the removal of the box in question permits the unstacker to resume its normal operation, which takes place when switch s|1 is again closed.
OPERATION Fig. 1 illustrates the unstacker 25 in the act of unstacking a stack S of boxes B. The operation starts by closing the open points of switch s-1 which constitutes the starting and stopping switch, which energizes the motor IIO and the motor I which drives the floor tracks |60 and I 59 through the chain IE6. Stacks S of boxes B are now placed upon the iioor track la and these are carried on this track towards the stacker 25. When the motor liti is energized without any stack being in the unstacker, this motor is halted the iirst time switch s-4 is opened by a cradle il passing over the zenith of its path of movement. At this time the other cradle TI is at the bottom of the unstacker and the arms 'i3 thereof are guided by guides I8! so that these turn forwardly into proper positions for lifting a stack S when the latter has been fed into the machine. After the halting of the motor il@ by the actuation of switch s-ll the iioor track continues to feed the initial stack S into the machine until the latter engages and actuates switch 3 2. This starts the motor I I 0 causing upward travel of one of cradles 'II immediately beneath the stack in the unstacker.
If switch s-l remains depressed while the initial stack S is engaging switch s-2 the floor track motor |55 is halted and remains de-energized until the gib I3 of the support 'i2 on that side of the unstacker engages switch s-S whereupon the motor its is re-energized causing the oor track to resume the delivery of stacks S to the unstacker 25.
As the uppermost box of a stack S being elevated in the unstacker 25 comes opposite the rollers Me the upper box B therein is forced inwardly against the beads 55 of the box guides 38 so that the corners of the box disposed inwardly will engage the rubber tired rollers 55 when this box comes opposite said rollers. This results as shown in Fig. l in the inner portion of the box B, thus engaging the lifter rollers 55, being lifted upwardly while the outermost portion of this box B still rests upon the box immediately there beneath.
About the same time said uppermost box comes into contact with the rollers 56 it also engages the rollers E39 of the pusher members E37 so as to lift the rollers ISS upwardly and swing the members i3? outwardly so that rollers i3d move away from over said uppermost box until said rollers arrive in an inwardly pushing position in which they are shown in Fig. 1G. This movement of rollers I 35 stretches the springs me which are connected at their opposite ends to the structure 98 and shaft ISE. This positioning of the rollers IBB and stretching of the springs i9@ is followed shortly by the inner portion of the uppermost box B being lifted by the rollers 55 into a position to pass over these rollers 55 which is accompanied by considerable acceleration due to the frictional engagement of the rollers 55 with the uppermost box E and the inward pressure of the rollers ISB, urged, as these rollers are, by the tensioned springs 195.
The rollers I3@ follow the uppermost box B inwardly as shown in Fig. l1 until the center of gravitv of said box is almost directly over the axis of the rollers 5S and the movement of this bcx over the rollers 5S has been accelerated to the point where it is rapidly discharged from over these rollers onto the conveyor 82.
In like manner each of the succeeding boxes of the stack S in the unstacker 25 is discharged singly over the rollers 5t and onto the conveyor 82.
A significant advantage of the present invention is to be found. in the fact that the mechanism for separating individual boxes, from the upper end of a stack of the same being elevated, does not operate in timed relation with the elevator but instead operates in timed relation with the contact of the upper face of the uppermost box with the rollers ISS. Considering the lifter rollers 56 and the stack guides 35 as guide means disposed alongside the rising stack, it is to be noted that irrespective of variations in the depth of the boxes B (within a reasonable range, of course), the box separating mechanism functions in timed relation with the engagement of the upper face of each uppermost box B with the rollers |39 to effect separation of this box from the stack and the discharge thereof over said guide means, as shown in Fig. 11. rFhe unstacker 25 is thus adapted for use on boxes varying as much as an inch in depth without causing any malfunctioning of the individual box separating mechanism at the upper end thereof. In prior unstackers this would be impossible because of the mechanical drive connection provided therein between the elevator and the box separating mechanism so that these operated in only a single xed timed relation with each other.
It is to be noted, therefore, that the rollers [35 perform three functions. They act as timing members in that they cause the box separating mechanism to function to separate the uppermost box from the stack in what is practically a iixed timed relation between said separation and the moment said upwardly moving box contacts said rollers. These rollers also perform the function of transmitting from the rising stack the power for stretching the springs i90 and thus imparting to these springs the motive power for separating the box and the stack when the separating mechanism is free to act. Finally, rollers 39 roll over the up-per outer corner of said uppermost box as shown in Fig. 10 so as to come into position alongside said box at the moment that its opposite side rises above the lifter rollers 55 whereby rollers |39 transmit to said box the impulse of the box separating mechanism so as to rapidly shift said box out of the path, along which the stack is rising, to a position over the rollers 55 the 'constant rotation of which completes the separation of said box from the stack initiated by the box separating mechanism.
The rollers 56 may thus be considered, in a sense, to comprise part of the box separating mechanism as well as forming a part of the guide means aforesaid.
The electrical system shown in Figs. 12 and 13 functions, in the operation of the invention above described, in the following manner. Closing the normally open contacts of starter switch S- energizes relay coil S-9-c closing relay contacts S-S-o, S92 and S-B-S thereby sealing in the energizing circuit of coil S-9-c. The closing of switch S-9-3 energizes the elevator motor switch coil S-l3-c starting elevator motor Sie. The closing of switch S-S-o energizes the floor track motor switch coil S-I-c thereby starting iioor track motor I 85. A stack restirrr on. the floor track will now be moved toward the unstacker.
This stack opens switch S-i upon contacting the same, thereby fle-energizing S-lZ-c and stopping motor with the stack resting on switch S-I and holding this open. Assuming' that one elevator cradle Il is now below switch 8 3 and rising, the gib 'I3 of that cradle momentarily closes switch S-S, as it passes the same, thereby energizing S-I-c and closing S-I t-I and S-I-Z which re-energizes S-I2-c and restarts the floor amarlo? the elevator is thus resumed.
Arriving in the elevator, this stack operates switch S-, opening the no nail closed terr mais thereof, which stops motor and closing` the normally open terminals with no result as S434: is already energized. After its engagement with switch S-3, the rising elevator cradle El continues upwardly and, at its zenithJ engages switch S-l which opens this switch with no effect because .SJ-2 is at that time actua-ted by the entering stack. Had this stach not yet arrived in the elevator', switch .f-2 would be unactuated and the opening of SJ; would stop the elevator energizing Si3-cin such an event the clel5 vator wo stack eng and x ould then have sto The lower cradle "El now rises beneati nd the stach in the ele a'fior and mov 'Y away from Si the normal. This doe@ the aina ent gib of the u movement or disposed. cra-:lle out oi eo S-JI, closes the latter and this e going.
Switches S-l a tance apart slightl along the bor.. discharge conveyor of these is contacted and held open long as said box is t' ectly opposite it. boxes are normally if c switches will be both open only a ja on the box discharge conveyor and ther taneous opening will de-energire S-i Sc and stop the elevator. As soon as this jam is relieved and one oi the swi ches S-il and S-E i-c-c closes a result, this will re-energize S-ltc and start the elevator.
Switches S2-T and Sl3T are overload cut- 4( outs incorporated respectively in the magnetic switches for the motors driving the elevator and floor track. 'In case overload on either motor, these overload sv tches operate to stop both motors.
Switches S-iel and E3-i5 manual switches for jogging respectively the motor for the elevator and the motor for the loor track.
rThe claims are:
l. In a box unstacxer, the combination or: an 5;) elevator adapted to lift a stack ol* boxes in column form along a path t aid stack;
a power driven rotary :trictlonal box lifter located horizontallyadjacent an upper portion of said path so the portion of an uppermost box 55 on said sLn comes into rictiona-l engagement path so as to be conost box as it rises therein; 'nounting member to so "Jonse to engagement or said member, shirt d path on the opposite side of the latter from L'. lifter; inea operating to press against a portion of said box opposite that side portion thereof which engages said lil' e:, whereby s niem er propels said box onto saro. lifter and the rotation ci sal-d lifter causes the movement o said box ther-cover to continue until said box is entirely removed from said and conveyor means for successively receiving boxes thus delivered from the upper end o stack. and over said lifter.
2. A combination as in claim l in which said member is provided with a pair of rollers which e tacterl by said uppern cause it to move, in said uppermost box said member out of s ffl 8 engage the uppermost box of said stacl: in the planes of the box heads.
8. A combination as in claim 2, in which the means for mounting said member includes linkage constraining the movement of said member to travel between a position in which it overlies and contacts said uppermost box, and a position disposed upwardly from the first position and outwardly away from over said uppermost box, and spring means constantly urging said member from said second position to said nrst mentioned position.
4. In a box unstacker, the combination of: a stack elevator; a rotary conveyor roller located horizontally alongside the path along which a stack of boxes is lifted by said elevator; power means to rotate said roller with the surface thereof rising adjacent said path; a box pusher member disposed in the path of said uppermost box as it rises toward the level of said roller; and resilient means for mounting said pusher member to cause it to resistingly yield upwardly, when engaged by said box, and away from over said box on the opposite side of said path from said roller, said means thereupon applying pressure horizontally through said pusher against said box, as the latter rises further, to propel said box onto said roller whereby frictional engagement of said box and said roller conveys said box over said roller.
5. A combination as in claim 4 in which said conveyor roller and said pusher each includes a pair of rollers engaging said box in the planes or the box heads.
6. A combination as in claim 5 in which said conveyor rollers have friction treads and engage and lift an adjacent side portion of an uppermost box above the next box therebeneath as said pusher rollers are yielding upwardly and outwardly from over upper edges of said box sides.
'7. A combination as in claim 6 in which inclined stack guides are provided in said planes beneath said conveyor rollers, said elevator lifting said stack while tilted against said guides; and a pair of pressure rollers resiliently pressing said next box against said guides as the uppermost box is being engaged by said conveyor rollers and pusher rollers.
8. In a box unstaclrer the combination of: a stack elevator for elevating a stacl; of boxes along a given path; a conveyor disposed at a given level. alongside said path for successively receiving the boxes of said stack as said boxes arrive at said level; a box pusher disposed in said path to be engaged by the topmost box o said stack as it rises toward said level; and resilient means for mounting said pusher to cause it to resistingly yield upwardly when engaged by said box, and away from over said box on the opposite side of said path from said conveyor', said means thereupon applying pressure horizontally through said pusher against said box, to propel said box onto said conveyor said pusher thereby being again extended into said path so as to be similarly engaged by the next uppermost box of said stack so that the action of sai-d pusher aforesaid is repeated on each of the boxes of said stack as they successively become the topmost box of the stack and are elevated toward the level of said conveyor.
9. In a device for breaking down a stack of articles superimposed one upon another in the form of a column, into a series of separate articles, the combination of: an elevator for lifting said stack of articles in column form along a path aligned with said stack; guide means disposed along one side of said path for engagement by said stack as said stack rises on said elevator; roller means; means for mounting-said roller means to suspend the same in said path so as to be contacted by the uppermost box of said stack as the latter is lifted by said elevator, said mounting means being yieldable, upon movement thus being imparted to said roller means, to guide said roller means along a course which is inclined upwardly and outwardly from said path on the opposite side of the same from said guide means; and resilient means connected with said mounting means so as to resist the travel of said roller means in response to the engagement of said uppermost box with the latter whereby power is transmitted from said ele- Vator through said uppermost box and said roller means to said resilient means, which power is applied reactively through said roller means to a side portion of said uppermost box as said roller means is shifted away from over said uppermost box and as the latter rises above said guide means to cause said power applied to said box through said roller means to propel said uppermost box from sai-d path over said guide means.
10. A combination as in claim 8 in which the return of said pusher into said path rapidly propels said uppermost box onto said conveyor, said pusher remaining in contact with said uppermost box and pushing the latter until the center of gravity of said uppermost box has closely approached a position over said conveyor, thereby assuring that travel of said uppermost box on said conveyor away from over said stack continues after the top face of the next rising box engages and retracts said pusher away from the aforesaid uppermost box to start the next box separating cycle.
11. In a device for breaking down a stack of rectangular boxes, having a uniform cross-section, and superimposed one upon another in the form of a column, into a series of separate boxes, the combination of: an elevator for lifting said stack of boxes along a path aligned with said stack; a conveyor roller positioned adjacent said path to be frictionally engaged by one side of each box in said stack as said box rises to the level of said roller; means for constantly rotating said conveyor roller; a pair of pusher rollers lying in the planes of the ends of said boxes; means for shiftably mounting said pusher rollers with the 1latter initiall; in a position over the ends of the uppermost box so as to extend approximately half way across said ends towards said conveyor roller from the opposite side or said box, said pusher rollers being shifted upwardly and away from said conveyor roller by the rising or" said uppermost box while said box is in contact with both said conveyor roller and said pusher rollers until said pusher rollers ride away from over said uppermost box so es to bear against said opposite side of said uppermost box; and yieldable means biasing said pusher roller mounting means to continually urge said pusher rollers towards their iirst mentioned position, aforesaid, whereby said pusher rollers, upon yielding away from over said box ends, push said box against said conveyor roller, thereby producing a sufficient frictional engagement between said rst mentioned box side and said conveyor roller to lift said side of said box Causing said side to ride up onto said conveyor roller, the pressure of said pusher roller against the other side of said box thereupon propelling said box over said conveyor roller until said pusher roller has been returned to its initial position, aforesaid, at which time the center of gravity of said uppermost box has closely approached a position directly over said conveyor roller.
ERNEST A. VERRINDER.
References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 832,433 Straub et al. Oct. 2, 1906 1,972,969 Allen Sept. 11, 1934 2,258,461 Marsden et al. Oct. 7, 1941